Process of cutting blocks of stone



July 25, 41933. J. B. NEWSOM- 1,919,800

PROCESS OF CUTTING BLOCKS OF STONE Filed Feb. 9, 1929 FIG.3

Patented July 25, 1933 :Unrrae s'mrss JOHN B. NEWSOM, F; BLOOMINGTON, INDIANA PROCESS OF CUTTING BLOCKS. 0F STONE Application filed. February 9, 1929. Serial No. 338,696.

The invention relates in general to the art of stone working, and, more particularly, to a new construction of stone block and to a method of making thesame.

According to the invention, pieces or slabs of natural or artificial stone may be pinched between knives or shears to cause the pieces 'or slabs to split or crack along predetermined lines, formingfractured surfaces on the split pieces, which bring out the natural beauty of the stone in a remarkable manner. any desired size including the size of ordinary bricks. The top, bottom and end faces of the blocks may be sawed or finished in the usual way, the exposed front face of the block being the fractured face. Various other features and advantages of y the invention will be apparent from the fol- '20 lowing particular description and from an inspection of the accompanying drawing.

Although the novel features which are believed to be characteristic of this invention will be particularly pointed out in the '25 claims appended hereto, the invention itself, as to its objects and advantages, the

.mode of its operation and the manner of its or anization may be better understoodby re 'erring to the following description 0 taken in connection'with the accompanying drawing forming a part thereof, in which Fig. 1 1s a perspective representing a block of stone, either natural or artificial,-

made according to the invention;

1 particularly to Fig. 1', a block of stone which 0 may be either natural or artificial is repre- The blocks may be made in Fig. 2 represents a section of a slab in p0-' sented. The top face 1 and bottom face 2, as Well as the end .faces 3 and 4 may be substantially fiat and smooth, preferably being formed by gang sawing or earborundum sawing in a manner well known in the 5%} art of stone cutting. The exposed front face 5 of the block, is broken or fractured as indicated and presents a rough and broken appearance, bringing out the natural beauty of the stone. It will be noted, however, to that restricted areas 6 and 7 at the edges of the exposed facee' at the top and bottom have a slightly different appearance, these portions being crushed in the pinching operation hereinafter described.

rough, it is in general flat and intersects its adjoining faces 1, 2, 3 and 4 in lines which are uneven but whose general direction is controlled by the knife edges hereinafter described. Obviously the crushed zones may be of any desired shape and may be continuous or discontinuous as the occasion requires.

It will be understood that the back face 8 may be broken or fractured like the front face, especially if the block is made according to the details of the process hereinafter set forth.

Referring now to Fig. 2,the knives 10 and 86' 11 of the pressor shears are indicated diagrammatically'and are shown as having V-shaped edges. The slab of stone which isfed between the knivesis indicated by 12 and its upper and lower surfaces 13 and14 are illustrated as smooth, having been cut by the usual sawing operation well known in the art of stone cutting. Surfaces 13 and 14 may however be irregular or broken if desired.

The height or thickness. of the slab 12 (distance between surfaces 13 and 14) may be equal to the height or thickness of the finished block (distance between surfaces 1 and 2) and the width of the slab in the .di rection of the length of the knives 10,-11 may be equal to the. length of the block (distance between end surfaces 3 and 4). The

slab 12 may be fed automatically or by hand between the knives 10, 11' which operate to It will be 65- -seen' that, although the exposed face 5 is form fractures indicated by the dotted lines 15. The feed may be so arranged that the knives operate on the slab at points spaced a distance apart equal to the width or depth of the desired stone block (distance between surfaces 5 and 8).

It will. be understood that the length of knives may be at least equal to the length of the block (the distance between end surfaces 3 and 4t) also that each finished block may have fractured front faces or fractured front and back faces while the remaining faces will preferably be relatively smooth and even.

To crack or fracture the slab, pressure is exerted upon the knives 10, 11 toward each other, the knives first engaging the upper and lower surfaces 13 and 14 of the slab, crushing small grooves 16 in the surfaces. After the knives have cut in the slab to form these grooves, the slab may be broken along the lines 15 of fracture indicated, continuing the pressure of the knives or by other means such as bending, thereby forming fractured surfaces on both pieces of the broken slab.

T Vhen the knives are symmetrical, as indicated in Fig. 2, the fracture is usually more or less flat or plane, as indicated in Figs. 1 and 2. In other words, the fractured faces, while rough and broken to bring out the natural beauty of the stone, nevertheless follow in general the direction of a plane. 1

If it is desired to produce blocks having convex or concave exposed faces, knives 20 and 21 of the shape indicated in Fig. 3 may be used. In this figure, one side 22 of each knife is substantially parallel to the direction of knife movement, while the other side 28 of the knife is inclined or oblique. When the slab 24 is pressed between these knives, the line of fracture 25 becomes in general curved, making the face of one severed block generally convex, and the face of the other severed block generally concave. It will be understood that these faces are rough and broken as in the blocks illustrated in Figs. 1 and 2 to bring out the natural beauty of the stone, but the general contour of the fractured surfaces is convex and concave respectively.

The areas 6 and 7 of crushing on the fractured exposed surfaces do not detract from the beauty of the stone to any extent and the formation of lines of crushing and resulting notches 16 in the opposed faces of the slab before the slab actually begins to break, assists materially in causing regular fractures. In other words, when a break does start, it naturally follows the if-shaped grooves, as they represent lines of weakness. If the grooves were not there, it is possible that the fracture would tend to run off at an angle and it would be more difficult to make blocks which are rectangular in shape.

It has been found that by practicing the invention as above described, very consis tent results can be obtained. However, flaws and imperfections in the stone make absolutely consistent and regular results impossible, but the percentage of defective bl cks can be kept quite small by paying close attention to the character of the stone fed between the knives.

It will be appreciated that a block of stone made according to the invention brings out the crystal structure, grain size and other natural beauties of the stone much better than sawed faces, and may be made more cheaply than in the case of hand chiseling.

The blocks can be made in any suitable size, and by proper selection of the stone almost any desirable'degree of roughness of face can be obtained. It hasbeen found that Indiana limestone lends itself particularly well to making blocks of the above kind, making blocks of exceptionally beautiful and attractive appearance. Thus it is possible to select a building face from a wide vaiation of possibilities if these blocks are used. If it is desired to present a smooth face on the building at any point, turning the blocks on their sides will expose the sawed,,relatively smooth faces. When using bricks having one face convex and the other concave, a course can be laid out by the mason exposing the convex face of each block or the concave face, as desired. Obviously a block may be formed with any desired number of broken sides such as four or six.

Heretofore the production of bricks and small blocks from stone has been prohibitive in cost because all six sides had to be cut with a saw. and this was not worth while for a small brick or stone. The shearing or pinching according to the present invention is much less expensive both as to the initial outlay for mach inery and in operating cost. Furthermore, but small power is necessary to operate a press or shearing machine to fracture large and hard stone even when the stone has tremendous crushing strength.

Another advantage of the present invention is that the knives may be adjustable in the machine so that by setting them to differ ent projected extents, different thicknesses of slab may be fed into the same machine.

While certain novel features of the inven tion have been shown and described and are pointed out in the annexed claims, it will be understood that various omissions, substitutions and changes may be made by those skilled in the art without departing from the spirit of the invention.

What is claimed is:

1. The method of making a stone building block whose thickness between top and bottom faces is great compared to the area of said top and bottom faces, which comprises applying, gradually, fracturing pressure along substantially straight lines on opposite top and bottom faces of a slab of stone, first'to crush grooves in said slab and then to crack said slab along said grooves into two pieces of stone having fractured faces extending between said lines, the fracturing pressure exerted on one piece of stone being greater than that exerted on the other pieceto cause the fractured surfaces to be generally curved in a direction from one of said substantially straight lines to the other, at least one of said pieces being a stone building block whose thickness between top and bottom faces is great compared to the area of said top and bottom faces.

2. The method of making a stone building block whose thickness between top and bottom faces is great compared to the area of said top and bottom faces, which comprises applying, gradually, fracturing pres-- sure along substantially straight lines between V-shaped knives disposed on opposite top and bottom faces of the slab of stone, 7 first to crush grooves in said slab and then to crack said slab of stone along said grooves into two pieces of stone having fractured faces extending between said lines, one of the side faces of said knives being substantially parallel to the direction of knife movement and the other side face of said knives being oblique to the direction of knife movement 

